Known in the art, there is the U.S. Pat. No. 4,913,258 of Hiroshi SAKURAI et al, granted on Apr. 3, 1990, in which there is described an outer-rotor type motor wheel, comprising a knuckle, a hub coaxially interlocked with the knuckle, a wheel disc rotatably attached to the periphery of the hub, a wheel secured to the periphery of the wheel disc, a rotor fastened to an outer side of the wheel disc from the direction of the outer side, and a stator coaxial to and spaced from the rotor by a small gap and fastened to the hub from the direction of the outer side. One drawback with this outer-rotor type motor wheel, is that in order to provide a powerful motor wheel having a high torque, high current has to be injected to the power line to energize the coil of the armature core even at zero speed. With this outer-rotor type motor wheel, a converter has to be provided. This converter is mounted inside the vehicule and can be very cumbersome. Such high current circulating through the power line produces heat which is energy loss and also requires a power line which can be quite heavy.
Also known in the art, there is the U.S. Pat. No. 754,802 of Ferdinand PORSCHE et al, granted on Mar. 15, 1904, in which there is described the combination of the axle, the wheel, the hollow journal for the wheel, the end of the axle projecting to the journal, and a pivotal connection between the axle and journal having its axial line disposed acutely to the plane of the wheel. Again, to produce a powerful motor-wheel, the current supplied to the sliding brushes, brought from outside of the motor-wheel has to be a high current. This high current will have to be brought through large diameter cables or wires to reduce energy loss.
Also known in the art, there is the U.S. Pat. No. 2,348,053 of J.E. BOWKER, granted on May 2, 1944, in which there is described an electrically-operated motor vehicle improvements comprising a plurality of wheels arranged to be driven, a dynamotot forming an integral part of each such wheel, and electrical circuit connections between switch banks and dynamotots and batteries to control the operation of the dynamotots as motors according to the position of a selector switch. Again, the armature windings will have to be .energized with a high current in order to produce a powerful motor, such high current will require large diameter cables to bring the energy from the batteries of the vehicle to the windings of the armature. As well known, such large diameter cables or wires are rigid, cumbersome and incovenient.
Also known in the art, there are the following U.S. Pat. Nos. that describe different kinds of motor-wheels 638,643; 643,854; 2,506,146; 2,514,460; 2,581,551; 2,608,598; 3,566,165; 3,704,759; 3,792,742; 3,812,928; 3,892,300; 3,897,843; 4,021,690; 4,346,777; 4,389,586; 1,709,255; 2,335,398; 3,548,965.
None of the above-mentioned patents shows the necessary means for reducing the diameter of the wires of the power line between the motorized wheel assembly and the power supply when a powerful motorized wheel assembly is needed.
It is an object of the present invention to provide an electrically motorized wheel assembly wherein a variable AC current can be provided to coils of the stator of the assembly, and wherein relatively small diameter flexible and less cumbersome wires or cables can be used to supply electrical energy to the assembly even when a powerful motorized wheel assembly is needed.
It is also a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly having a ratio R.sub.1 /R.sub.2 as close as possible to 1 where R.sub.1 is the distance between the air gap of the motorized assembly and the axis of rotation of the assembly, and R.sub.2 is the distance between the surface of a rim fixed onto the assembly, adapted to receive a tire, and the axis of rotation of the assembly.
It is also a further object of the present invention to provide a motorized wheel assembly that reduces heat production and energy loss.
It is also a further object of the present invention obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly that is provided with means for cooling down the assembly when it is operating.
It is a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly having a reduced weight while being compatible with standard braking system, suspension system and steering system.
It is a further object obtained by a preferred embodiment of the present invention to provide a motorized wheel assembly which is detachable from a suspension arm.